Motorized self-correcting automatic convertible top

ABSTRACT

This invention relates to a system and method for monitoring and controlling the operation of a motorized convertible top such that it may be extended and retracted automatically. The system and method of the present invention monitors the movement of the various components to provide fluid, simultaneous motion. It further detects and corrects improper alignments that may result in damage to the top due to overlapping elements or binding elements, and stores error information useful in diagnosing and repairing unrecoverable errors.

RELATED APPLICATIONS

This application is a continuation-in-part of Ser. No. 817299 now U.S.Pat. No. 5,225,747, filed Jan. 6, 1992, for "Single-Button ActuatedSelf-Correcting Automatic Convertible Top", by James A. Helms and GeorgeA. Alderton, IV and assigned to the present assignee.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention relates generally to automobile convertible tops, andmore particularly to an automobile convertible top that can be openedand closed automatically.

2. Description of the Related Art

In the field of automobile design, convertible tops have been employedto provide the consumer with versatile styling. Most people are familiarwith manual convertible tops, which are latched and lowered by hand.However, over the years, many different types of automatic andsemi-automatic convertible tops have been developed. Generally, theseconvertible tops utilize one or more motors to move the various linkagesand other movable elements from an extended (or top closed) position toa retracted (top open) position. Through the aid of motorized movement,the user can raise and lower the convertible top more easily.

However, simply providing for motorized movement of the convertible topis not enough. For example, there are known motorized convertible topsthat provide for limit sensors on the elements to determine whether theelements are in the "full retracted" or "full extended" position.However, such systems provide no information as to whether the linkageelements are simply near, rather than being at, one of the two fullyarticulated positions or not. As a result, these known systems, whilebeing capable of causing the convertible top be opened and closedautomatically, require each sensed element to reach an extreme positionbefore commencing the movement of the next element in the sequencenecessary to accomplish the desired movement of the convertible top.Thus, it would be advantageous if a motorized convertible top systemcould allow simultaneous movement of various elements so as toaccomplish the opening and closing of the convertible top using a seriesof movements that are more fluid and continuous and that both reduce thetime necessary to accomplish the movements as well as improving theaesthetic appearance of the movements.

Another disadvantage of known motorized convertible tops is the factthat the elements may bind as the movements are sequenced, increasingthe load on the motors and risking damage to the motors or elements asthe motors try to "force" the elements to move. Especially when tryingto accomplish simultaneous movement of multiple elements, the fact thatone element may be slightly inhibited in its movement means that theother moving elements will reach their desired position sooner than willthe binding element. Allowed to continue uncorrected, this misalignmentof elements can result in the convertible top being cocked in anundesirable position and may cause damage to the convertible topmechanism. Therefore, it would be desirable if there were some way tomonitor the movement of critical elements while they are movingsimultaneously so that remedial action can be taken in the event that amisalignment situation arises. The remedial action could includestopping the movement of other elements while the binding element isstill moved, allowing the slower, binding element to "catch up" with theother elements. The remedial action could also include reversing themovement of some elements in order to realign the convertible top, and,once realignment is achieved, resuming normal movement of the elements.The remedial action could also detecting an unrecoverable misalignmentand shutting down the motors before the motors are overburdened.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a systemand method for lowering and raising an automobile convertible top wheremotive means, such as electric motors, move the various structuralelements of the convertible top. Sensors are associated with theconvertible top's structural elements whereby the system determines theinstantaneous position of the various structural elements as they aremoved and commands further movement based upon the sensed positions ofthe elements. One advantage of the present invention is that thestructural elements can be moved simultaneously to achieve a more fluidsequence of movements and to decrease the amount of time it takes toextend and retract the convertible top.

Another advantage is that, because the instantaneous positions of thevarious structural elements are being monitored, the system and methodare capable of instituting remedial action in the event that thestructural elements become misaligned during the sequence of movements.A further important feature of the presently preferred embodiment isthat the monitoring of the convertible top's structural elements isaccomplished through the use of only a few sensors, thereby simplifyingthe assembly of the system and reducing the cost associated therewith.Another feature of the presently preferred embodiment is that the systemand method are capable of diagnosing failures within the system, andgenerating failure indications, whereby the automobile owner or aqualified service person can interpret the error information and performthe necessary repairs.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the present invention willbecome more apparent after understanding the following description ofthe presently preferred embodiment in conjunction with the drawings inwhich:

FIGS. 1 through 8 are diagrams illustrating the movement of the elementsof the convertible top as it is retracted and extended;

FIG. 9 is a functional diagram detailing the relationship between themotor, sensor, structural element and controller at one particular pivotpoint in the convertible top mechanism; and

FIGS. 10 and 11 are flow charts depicting the control methodologyemployed to ensure proper sequencing of the various structural elementsas the convertible top is retracted and extended.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As illustrated in FIGS. 1 through 8, the present invention is directedtoward a mechanism which can automatically raise and lower an automobileconvertible top. As can be appreciated by those of ordinary skill in theart, while each different type of automobile requires a differentconvertible top suited to the particular vehicle, the concepts disclosedherein are equally applicable to a wide variety of configurations. Inthe presently preferred embodiment, the portions of vehicle 10 ofinterest for the purposes of this discussion are the convertible top 12which is stored in a compartment beneath a tonneau cover 14, the rearquarter windows 16 and the front side windows 20. Also, although notspecifically shown in the drawings, the vehicle has a trunk lid locatedrearward of the tonneau cover. Generally, the tonneau cover 14 must beraised and the windows 16, 20 must be lowered before the convertible top12 is lowered or raised. This insures that the top 12 will be properlystored in the compartment beneath the tonneau cover 14 and also insuresthat the windows 16, 20 are clear of the top 12 as it moves, therebypreventing damage. Similarly, the trunk lid generally should not beopened when the tonneau cover 14 is raised.

More particularly, the lowering, or retracting, of the convertible topoccurs in the following manner. In this embodiment, the convertible topcannot be raised or lowered unless the vehicle is stopped. This preventsthe driver from accidentally moving the top while under way, and can beaccomplished several ways. One way is to determine whether thetransmission shift lever is in "park," and another way involvesmeasuring wheel speeds and/or vehicle speed to see if the speed is zero.Since the transmission shift lever position, wheel speeds and/or vehiclespeed are already monitored on most cars to accomplish other functionssuch as engine fuel management and anti-lock braking, tapping into oneor more of these signals would be fairly simple for one of ordinaryskill.

With the car stopped, the first step, as shown in FIG. 1, involvesunlatching the top 12 from the header 22. In this embodiment, screwmotors unhook J-hooks latched to the header 22. This is disclosed inassignee's issued U.S. Pat. No. 5,058,939, the disclosure of which ishereby incorporated by reference. However, it can also be appreciatedthat other forms of latches could be used. Additionally, the latchescould be manual, with conventional sensors to indicate whether theperson operating the car has yet unlatched the latches. Next, to preventaccidental collisions between components, the trunk lock release isdisabled to prevent the trunk lid from being opened into the path of themoving tonneau cover 14 and/or top stack 12. Once the latches areunlatched and the trunk release disabled, the rest of the movementsnecessary to lower the top 12 can commence.

The next movement in the sequence, shown in FIG. 2, is the raising ofthe rear bow 24 so that the tonneau cover 14 can be raised, and thelowering of the forward side windows 20 and rear quarter windows 16. Theforward side windows 20 and rear quarter windows 16 are lowered to allowthe top to move freely without worry of damaging the windows 16, 20. Inthis embodiment, the windows have an "express down" feature which permitthe windows to be lowered completely after only holding down the windowcontrol button for a few seconds. Since express down requires specialcircuitry to allow such a feature, the control system of the presentlypreferred embodiment exploits this circuitry to accomplish the automaticlowering of the windows when the convertible top is set in motion.

Once the rear bow 24 reaches a position clear of the sweep path of thetonneau cover 14, the tonneau cover begins raising, as shown in FIG. 3.Next, once the tonneau cover 14 reaches a position clear of the sweeppath of the rear bow 24, the rear bow lowers, as shown in FIG. 4, andthe main rail of the convertible top 26 begins lowering into thecompartment 28 beneath the tonneau cover 14, as shown in FIGS. 5-7.Finally, once the top is retracted into the compartment 28 and is clearof the sweep path of the tonneau cover 14, as shown in FIG. 7, thetonneau cover 14 is lowered to cover the compartment 28, and the windowsraised as shown in FIG. 8. To raise the convertible top 12, the sequenceof movements are simply reversed. The linkages forming the support frameof the convertible top and the motors used to move the linkage can be ofconventional design, such as disclosed in U.S. Pat. Nos. 3,180,675 and3,312,058.

In order to provide the unique control of this invention which allowsthe various elements, such as the latches, rear bow 24, tonneau cover 14and main rail 26 to move in a fluid, simultaneous fashion, a uniquearrangement of sensors is provided. As illustrated in FIG. 9, each topstack position sensor in the preferred embodiment takes the form of arotary variable resistance device or potentiometer 30 mounted at thepivot point of a pair of elements or links. When mounted at a pivotpoint between links, the sensor senses the relative position of one linkwith respect to the other. Similarly, when mounted at a pivot pointbetween a link and the vehicle's chassis, the sensor senses the relativeposition of the link with respect to the chassis. It can thus beappreciated that these sensors should be provided at each critical pivotpoint in the mechanism. Here, Applicants have discovered that only threetop stack position sensors are required to achieve full control of thetop. The three critical points of relative movement requiring sensingare: 1) the position of the rear bow 24 with respect to the main rail26; 2) the position of the main rail 26 with respect to the vehiclechassis, or body; and 3) the position of the tonneau cover 14 withrespect to the vehicle body. The position sensors are mounted at thesethree critical pivot point 31, 32 and 33. For example, as detailed inFIG. 9, the sensor provided at the pivot point 31 of the rear bow 24 isshown diagrammatically in greater detail. Here it can be seen how thepotentiometer 30 measures the relative position between the rear bow 24and the main rail 26. The pivot point sensors are electrically connectedto the controller 34 which monitors the positional information providedby the sensors (i.e. voltage or amperage) and, in response to thesesignals, commands the movement of the convertible top 12.

In this embodiment, cantilevered DC motors move the various elements,although it should be appreciated that other motive means could beutilized, such as, for example, hydraulic motors. However, DC motorshave been selected for several reasons. First, the power draw of a DCmotor is directly proportional to motor torque. This allows the loadingof the motor to be monitored to protect against overburdening the motor.Second, DC motors can be manually back-driven more easily than canhydraulic mechanisms. This helps ensure manual override of the systemcan be effected in the event the system fails.

In order to move the tonneau cover 14, rear bow 24 and main rail 26, themovement of the DC motors is governed by the controller 34. Asillustrated, the rear bow motor 36 raises and lowers the rear bow 24,and the rear bow potentiometer 30 measures the relative angular positionof the rear bow 24 with respect to the main rail 26. In response to thedetected position of the rear bow, as well as the positions of the otherelements, the controller 34 issues commands to the rear bow motor 36 toraise or lower the rear bow 24 as needed. The other motors are similarlycontrolled. Likewise, the control of the windows involves the use ofwindow drive motors and window position sensors which detect whether thewindows are in the full up or full down position.

The interaction of the controller 34, DC motors, sensors and variousinterlocks can be better understood by referencing the flow charts ofFIGS. 10 and 11. The controller 34 is powered by the vehicle'selectrical system, and includes driver circuits for providing current tothe motors, A/D converters for sensing the stall condition of the motorsand for the instantaneous positional information provided by thepotentiometers and position sensors, and command input lines forreceiving and interpreting the "top up" or "top down" signals issued bythe automobile driver through the up/down switches 38, all of which areinterfaced to a microprocessor. It can be appreciated by those ofordinary skill in the art that the electronics and circuitry comprisingthe controller 34 can take a variety of forms, however themicroprocessor, converters and drivers selected for this embodimentprovide a convenient means by which to execute the invention.

In this embodiment, the controller 34 monitors the linkage elementpositional information provided by the sensors to determine theinstantaneous position of the linkage elements. It also monitors sensorsassociated with latches, interlocks and position switches to determinepositional and status information of components such as the header andrear bow latches, the trunk release solenoid, the windows and whether ornot the vehicle is stopped. The controller 34 also monitors for a stallcondition at the motors to determine if a motor is being unduly loaded,such as would occur if the linkage being driven by the motor werejammed. Within the logic circuitry of the microprocessor of thecontroller 34 are instructions for interpreting the monitoredinformation and for directing current to the motors to drive the motorsin accordance with the action desired by the automobile driver.

In this embodiment, the driver is provided with "up" and "down" buttonslocated on the dashboard. These directional control buttons 38 areelectrically linked to the controller 34 and determine which sequence ofmovements of the convertible top 12 are desired. As shown in FIG. 10,the general control system logic progresses in the following manner. Ifthe driver presses the "up" button and the top 12 is already fullyraised, no action is taken, as indicated by function block 50 and actionnmenomic 52. Similarly, if the "down" button is pressed while the top 12is fully lowered, no action is taken 60, 62. However, the normal courseof events would be that the "down" button is pressed when the top 12 isup, and the "up" button pressed when the top 12 is down.

It should be noted that, in this embodiment, the driver must continue todepress the "down" button for the top 12 to continue moving down, andmust continue pressing the "up" button for the top to continue movingup. This allows the driver to pause or even reverse movement of the topby simply releasing the button and pressing the opposite direction. Oneof ordinary skill can appreciate that the driver may wish pause movementof the top to perform other tasks, or may wish to reverse movement ofthe top if he changes his mind about opening or closing the top.

When the top is up 50 and the "down" button is pressed, the controller34 senses the directional command desired by the automobile driver andbegins initiating the sequence of movements necessary to lower the top12. First, provided the vehicle is stopped, the J-hooks are unlatched,the windows are lowered and the rear bow 24 is raised 70 until thepositional sensors indicate that the rear bow is in the up position andthe tonneau cover is in the down position 72. Provided the "down" buttonis still being depressed, the next action is to raise the tonneau cover74. The positional information provided by the sensors should then bethat the rear bow, main rail and tonneau cover are in the up position76. Now that the tonneau cover is clear, the rear bow is lowered 78,leaving the main rail and tonneau cover up 80. Next, the main rail islowered 82, leaving only the tonneau cover in the up position 84.Finally, the tonneau cover is lowered and the windows raised 86,completing the lowering 60 of the convertible top 12. Of course, as waspreviously disclosed, none of these movements would be allowed to takeplace unless the car is stopped. Likewise, the trunk release would bedisabled to prevent accidental opening of the trunk during thesemovements.

To raise the convertible top 12, the process is simply reversed. Thus,the controller senses the "up" command issued by the automobile driverand begins the sequence of actions necessary for raising the top 12.First, the tonneau cover is raised and windows lowered 90, leaving themain rail and rear bow in the down position but the tonneau cover in theup position 84. Once the tonneau cover is clear, the main rail is raised92 so that both the tonneau cover and main rail are in the up position80. Next, the rear bow is raised 94 so that all elements are in the upposition 76. Once the rear bow is clear of the sweep path, the tonneaucover is lowered 96, leaving the main rail and rear bow up 72. Finally,the rear bow lowers, the J-hooks latch and the windows raise 98,completing the sequence of motions necessary to raise the top.

As shown in FIG. 11, the actual logic process includes the steps ofinitializing the controller upon power-up 100 and resetting the logiccontrol sequence 102. Next, the controller determines the status of thevehicle parameters, reads the position sensor and directional commandswitch information 104, and determines the position of the linkageelements with respect to the directional command desired 106. Based uponthis information, the proper movement in the sequence of movements isselected 110 and commanded 112-124. It can be appreciated from thisdiagram that while each given motion sequence is executed 112-124, thecontroller returns to the beginning of the control logic sequence andreassesses the positional and direction information 104, 106 in order todetermine 110 the next desired motion 112-124.

Since people normally only open the convertible top of an automobilewhen the weather is pleasant, the top may remain up and the motorizedconvertible top mechanism remain inactive for long periods of time, suchas during the winter. Because of this, the presently preferredembodiment employs current wetting during the initialization step 100.During current wetting, a short burst of electrical current is sentthrough the motor driver circuitry. This short burst of current is notenough to actually energize the system and cause movement, but is ratherdesigned to ensure the various connectors and relay contact points donot become corroded during their period of dormancy. For example, theup/down button 38, being a mechanical device, swipes away any buildupevery time the driver depresses the button. However, since theconnectors are rarely disengaged to inspect for and remove buildup, thecurrent wetting pulse travelling through the connectors during each andevery initialization sequence helps retard the growth of buildup.Moreover, the controller can monitor the response to the current wettingpulse to help detect circuit interruptions, such as opens or shorts,during initialization.

Also, it should be appreciated that, prior to executing a selectedaction 110, the controller 34 first ensures that the vehicle is stopped.Presuming that the vehicle is equipped with wheel speed sensors, thevehicle is considered stopped when the wheel speeds are all zero.Furthermore, once movement of the convertible top is undertaken anduntil the top reaches the fully opened (FIG. 1) or fully closed (FIG. 8)positions, the trunk lid release is disabled. This prevents the driverfrom accidentally releasing the trunk lid while the convertible top isin motion, and helps prevent damage to both the convertible top and thetrunk lid.

The presently preferred embodiment further includes an interlock whichinterfaces with the automobile's alarm system. When the convertible topis either fully up or fully down, a signal indicating such istransmitted from the convertible top controller 34 to external devices,such as the auto alarm system. For example, in the presently preferredembodiment, when the convertible top controller 34 senses that the topstack is fully up, an "up" relay is latched. The latching of the relaycan thereafter be monitored by external devices, such as the alarmsystem, so that appropriate action may be taken. In the case of an autoalarm, information as to whether the top stack is fully up or fully downmay be used to affect the alarm mode. Finally, the convertible topcontroller 34 provides information to other vehicle controllers via thevehicle's controller bus. This allows alert messages to be displayed tothe driver and enables the other vehicle controllers to modify operatingcharacteristics as needed to accommodate the actions of the convertibletop.

In practice, the control logic progresses as described in conjunctionwith FIG. 10, with the additional features of detecting improper linkagepositioning and/or excessive motor loading, and selects the motionsequence 112-124 necessary to remedy the situation. Thus, for example,if the controller 34 is currently commanding the tonneau cover to raise112 and a stall condition is detected at the motor driving the tonneaucover, the controller stops the motor 102 and reassesses the positionalinformation 104 to determine if another action is required. Similarly,in the event that the tonneau cover is being raised 112 but the rear bowslips into the path of the tonneau cover, the positional information 104will reveal this potentially damaging situation and initiate the raisingof the rear bow to insure the tonneau cover has proper clearance tomove. Finally, in the event that an unrecoverable error occurs, the upand down buttons can be depressed simultaneously 130 to reset thesystem. Upon resetting, qualified service personnel can access thecontroller 34 and receive error information such as whether one of thesensors has become grounded or shorted or whether one of the motors isexperiencing difficulty. Thus, service can be provided more quickly andcheaply because the convertible top system is self-diagnosing.

More particularly, the error detection and logging scheme employed inthe presently preferred embodiment utilizes several unique concepts.First, instantaneous position information can be utilized to allowoverlapping, or simultaneous, movements. Second, the instantaneousposition information can be used to determine whether the top is movingas desired or if an error has occurred. Third, the instantaneousposition information allows the controller to command those precisemovements necessary to achieve the fluid opening and closing of the topwithout risking accidental overlap collisions between elements. Finally,the instantaneous position information allows the controller to initiateremedial action in the event an overlap condition or stall condition isdetected.

First, the manner in which instantaneous positions are monitored will bedescribed in greater detail. For any two given elements, there exists arange of positions where the sweep path of the elements intersect.Outside of these ranges, the elements can move freely without worry ofcollision. However, within that range, care must be taken to avoidaccidental collision between simultaneously moving elements. In thisembodiment, the elements which have intersecting sweep paths are therear bow and the tonneau, the main rail and the tonneau, and the mainrail and header latch. Additionally, the controller should be aware ofthe latched state of the header and rear bow latches. For the varioustop stack elements, the ranges of motion can be categorized into fourstates: the first state corresponding to a first extreme position, thelast state corresponding to the opposite extreme position, and thesecond and third states corresponding to the beginning and end,respectively, of the range where the element's sweep path intersectsanother element's sweep path. For example, as measured by thepotentiometers, the lowest possible position is given a state definitionof "State 0". Likewise, the upper most position is given a statedefinition of "State 3". When moving from low to high, the point atwhich overlap starts is given a state definition of "State 1" and theposition where overlap ceases is given a state definition of "State 2".Using the state definitions of 0 through 3, it can be appreciated by oneof ordinary skill in the art that binary coding may be used to representthese states. Thus, the low position is represented by binary code 00,the lower boundary of the overlap range represented by 01, the upperboundary of the overlap range represented by 10, and the upper mostposition by 11. For elements such as the windows, wheel speeds, headerlatch and rear bow latch, a binary code of simply 0 for down, stopped,or unlatched and 1 up, moving or for latched, respectively, willsuffice. Using these state definitions, a hexadecimal status word can beformed.

The status word formed by the logic process of the presently preferredembodiment is an 8-bit word where

Bit 7=header latch state

Bit 6=rear bow latch state

Bit 5,4=main rail position

Bit 3,2=rear bow position

Bit 1,0=tonneau position

While it is convenient to use an 8-bit word as the status word, it canbe appreciated by one of ordinary skill in the art that the order of thestatus bits could be changed and the number of status bits in the statusword could be increased or decreased to provide information regardingother status items. For example, in an alternative embodiment, a statusbit is provided to indicate whether the vehicle is stopped (0 formoving, 1 for stopped) instead of the header latch status bit.

Using a status word format, every possible combination of positions canbe described as a two digit hexadecimal number. For example, with theconvertible top up and the rear bow latched, the status word would read40, or 01000000, which corresponds to

Bit 7=0, header unlatched or header latched not monitored,

Bit 6=1, rear bow latch,

Bit 5,4=00, main rail fully extended,

Bit 3,2=00, rear bow fully extended,

Bit 1,0=00, tonneau fully extended.

As can be appreciated, in this example, the header latch status bitequalling 0 when the convertible top is fully up and latched wouldindicate that the header latch is not monitored. If the car wereequipped with a header latch which was monitored, the status word wouldbe 11000000, or CO in hexadecimal. Using the status bit to form statuswords, the top down sequence, by state, can be represented as follows:

Header Latch status bit, 1=latched, 0=unlatched

Rear Bow Latch status bit, 1=latched, 0=unlatched

Main Rail Position bits, 00=top up, 11=top down,

01,10=sweep collision region

Rear Bow Position bits, 00=bow down, 11=bow up

01,10=sweep collision region

Tonneau Cover Position bits, 00=down, 11=up

    ______________________________________                                        11000000                                                                             C0    top is up, header is latched and rear bow is latched             01000000                                                                             40    top is still up, unlatch header, leave rear bow                               latched                                                          00000000                                                                             00    now unlatch rear bow                                             00000100                                                                             04    rear bow starts raising up and is now in overlap                              region                                                           00001000                                                                             08    rear bow continues raising                                       00001101                                                                             0D    rear bow finishes going up, while tonneau cover                               starts raising up                                                00001110                                                                             0E    tonneau cover continues raising and is now in                                 overlap region                                                   00011111                                                                             1F    tonneau finishes going up, while main rail starts to                          lower                                                            00101111                                                                             2F    main rail continues lowering and is now in overlap                            region                                                           00111110                                                                             3E    main rail finishes lowering, while tonneau cover                              starts to lower                                                  00111101                                                                             3D    tonneau cover continues lowering and is now in                                overlap region                                                   00111100                                                                             3C    top is down                                                      01111100                                                                             7C    top is down and tonneau cover is latched                         ______________________________________                                    

Similarly, the top up sequence, by state, can be represented as follows:

    ______________________________________                                        01111100                                                                             7C    top is down and tonneau cover latched                            00111100                                                                             3C    unlatch tonneau cover                                            00111101                                                                             3D    start raising tonneau cover                                      00111110                                                                             3E    continue raising tonneau cover                                   00101111                                                                             2F    finish raisins tonneau cover, while main rail starts                          raising                                                          00011111                                                                             1F    continue raising main rail                                       00001110                                                                             0E    finish raising main rail, while tonneau cover begins                          lowering                                                         00001101                                                                             0D    continue lowering tonneau cover                                  00001000                                                                             08    finish lowering tonneau, while rear bow starts                                lowering                                                         00000100                                                                             04    continue lowering rear bow                                       00000000                                                                             00    top is up                                                        10000000                                                                             80    latch header                                                     11000000                                                                             C0    latch tonneau cover                                              ______________________________________                                    

Using this scheme, the instantaneous position can be readily interpretedand examined to ensure undesirable overlapping collisions do not occur.Specifically, a table can be implemented in software where, for everypossible combination of movements, the next proper movement can becharted. This can be better understood by referencing Chart 1, below.

    __________________________________________________________________________    0x    1x  2x 3x  4x 5x                                                                              6x                                                                              7x  8x 9x                                                                              Ax                                                                              Bx                                                                              Cx  Dx                                                                              Ex  Fx                             __________________________________________________________________________    x0                                                                              dn04           dn00       dn00     dn40                                       up80           upC0       upC0     upXX                                     x1                                                                              ed03                                                                        x2                                                                              ed03                                                                        x3                                                                              ed0F                                                                        x4                                                                              dn08                                                                              ed18                                                                      up00                                                                        x5                                                                              ed08                                                                        x6                                                                              ed07                                                                          eu0A                                                                        x7                                                                              eu0B                                                                          ed0B                                                                        x8                                                                              dn0D                                                                              ed1D                                                                      up04                                                                        x9                                                                              ed0C                                                                          ed08                                                                        xA                                                                              ed0E                                                                          eu0E                                                                        xB                                                                              ed0F                                                                          eu0F                                                                        xC                                                                              ed0F       dn7C       dnXX               edRR                                 eu08       up3D       up3C               euRR                               xD                                                                              dn0E                                                                              ed1E   dn3C                                                               up08       up3E                                                             xE                                                                              dn1F                                                                              ed1F   dn3D                                                               up0D       up2F                                                             xF                                                                              ed1F                                                                              dn2F                                                                              dn3E                                                                  eu0C                                                                              up0E                                                                              up1F                                                                __________________________________________________________________________

From the foregoing, it can be appreciated that the "dnNN" entriescorrespond to the next state desired when lowering the top, while the"upNN" entries correspond to the next state desired when raising thetop. For example, by examining cell "1F," it can be seen that the nextdesired state is 2F when lowering the top and is 0E when raising thetop. The dnXX and upXX entries correspond to positions which terminatethe lowering and raising sequences, respectively, Thus, 7C correspond tothe top being fully down, while C0 corresponds to the top being fully upand latched. While a separate error operation table may be provided, itcan be appreciated that a single table can include both normal and erroroperations handling states. Here, a single table is employed because itconserves controller memory, which is often be a precious resource whendealing with microcomputers. These error corrective position andmovements are denoted with "euNN" and "edNN", where "eu" stands for aposition error detected while moving the top up, and "ed" for a positionerror detected while moving down.

As shown in the operation state table, for example, a state of 00001001,or 09 in hexadecimal, when the top is going down corresponds to the rearbow not having raised beyond the sweep path of the tonneau cover, whilethe tonneau has entered the sweep path of the rear bow. This means thata potential collision exists, or may have already occurred, between therear bow and the tonneau cover, which is undesirable. In this instance,to correct the improper positioning, the rear bow should be raised andthe tonneau cover should be lowered. Thus, the desired state found inthe error operation table in cell entry 09 is ed0C, which corresponds tomoving the rear bow until it is fully up and moving the tonneau coverfully down. As can be seen, for those error states from where recoverymay be feasible, the next, or recovery, state is charted. Thus, thestate table provide information for both normal operations and errorhandling operations. Also, there are position error states for whichrecovery should not be attempted. These are denoted as "euRR" and"edRR." For these unrecoverable states, the position informationindicates that the components are so misaligned as to indicate thesystem has already become too misaligned to attempt recovery, or thatthe position detectors have become instable or have failed. In eitherinstance, because the system should not attempt to correct the error,any state of "RR" causes a fault code to be logged. The movement anderror states illustrated here were provided for the purposes ofexplanation, and should not be construed as constituting the entirestate definition table or of constituting the only manner in whichmonitored positional information and desired actions can be cataloged.Moreover, the building of a state table is well within the ordinaryskill in the art.

Based upon the state table definitions, the motors for the tonneaucover, rear bow, and main rail are driven either forward or backward toachieve the desired motions. For example, in cell 0E the next desiredstate when lowering the top is "dn1F." Consequently, the motor movementsnecessary to achieve "dn1F" include energizing the tonneau cover motorto continue raising the tonneau cover, and energizing the main railmotor to begin lowering the main rail. It can be appreciated that eachnext state command has a unique combination of motor movements necessaryto achieve that state.

In addition to monitoring the instantaneous position of the variouselements to detect and correct misalignments, the presently preferredembodiment also monitors the motors to detect stall conditions. Here, astall exists whenever the motor power draw, which is proportional tomotor torque, exceeds a predetermined threshold for more than apredetermined amount of time. Whether or not a motor is stalled is usedby the controller in several ways. First, when the motor is moving itsassociated control element to an extreme position, a detected motorstall indicates that the element has reached the desired extremeposition. For example, when raising the convertible top, the main railmotor rotates the main rail from the retracted to the fully extendedposition. As the controller commands the motor to move the main rail tothe fully extended position, the instantaneous position informationprovided by the main rail potentiometer provides an indication of theposition of the main rail. However, by including the main rail motorstall condition, the controller can, with a greater degree of certainty,conclude that the main rail has achieved the full up position. This isbecause when the main rail potentiometer indicates the main rail hasreached the full up position, the main rail should indeed be fully upand incapable of being extended up further by the main rail motor.Therefore, the stall reading on the motor serves to confirm thepositional information. In a similar fashion, a stall condition detectedat a motor when the potentiometer indicates that the monitored elementis at an intermediate position is an indication that a misalignmentcondition may exist. For example, when lowering the convertible top, therear bow must move up and out of the way before the tonneau cover can beraised to expose the boot well. Therefore, the detection of a stallcondition on the tonneau cover motor when the tonneau cover is at anintermediate position serves to confirm the positional information fromthe rear bow indicating that it is also at an intermediate position andhas collided with the tonneau cover. Moreover, the detected stallconditions on the motors is used to generate error logging informationwhen, despite attempts to initiate remedial action to correct amisalignment, the controller detects that the motor remains stallednonetheless. Such a situation indicates that remedial action will not besuccessful, and that the convertible top has either become misaligned orone of the linkage points has become jammed so that the convertible topcan no longer be reliably retracted and extended automatically. Finally,the motor stall condition can be used as a calibration variable. In thismode, a particular convertible top element is cycled between the fullyextended and fully retracted positions. By determining the potentiometerposition information corresponding to the positions where the motorstalls, the controller can calibrate the potentiometer position valueinformation corresponding to the element's extreme positions. Employingthis calibration feature reduces the need for the potentiometer to beprecisely placed during assembly, instead allowing the controller toadapt to the particular characteristics of the convertible top system.

In the event an abnormal position is sensed from which recovery shouldnot be attempted or from which recovery was attempted but wasunsuccessful, the controller generates error logging information. Theerror logging information is stored by the controller so that servicepersonnel can interrogate the controller regarding the error, whichassists the service technician in pinpointing the problem. In thisembodiment, the error logging information is prioritized according tothe rank of the error. More serious errors are given a higher rank thanless serious errors. However, errors, regardless of rank, which occurduring the operation of the convertible top over time are logged inmemory so that service personal may interrogate the information toprovide accurate diagnosis of potential or existing difficulties.Specifically, when an error is detected, the error is assigned a rank.Next, the controller interrogates the error logging information todetermine if that error has been previously logged. If the fault has notbeen previously logged, a counter associated with that fault isincremented but the fault is not yet technically logged. This featureavoids the logging of an error condition when the error was the resultof an aberration rather than an actual error condition. Therefore, onlyonce an error is detected and its error counter indicates that it hasalready occurred at least once before the error is logged.

The controller stores error logging information in non-volatile memory,allowing the error information to be retained between ignition cycles.Therefore, the error log may include information about errors which haveoccurred days, weeks, or even months earlier. However, as in the case ofall memory devices, the memory in which the error logging information isstored is limited. Therefore, as one of ordinary skill in the art canappreciate, once the error logging buffer becomes filled, the controllermust decide between deleting old error information or failing to recordthe current information. In this embodiment, in the event the error logbuffer becomes filled, lower rank errors are deleted in favor of storinghigher ranked errors. To further conserve the error logging memory, thepresently preferred embodiment does not permit the logging of a low rankerror condition unless it has occurred at least two more times after itis first detected. This is in contrast to the logging of higher rankerrors, which are logged on the first subsequent occurrence after theerror has been detected. The logging of higher and lower rank errorcodes are further prioritized by the assigning of error occurrencecounts. As was just discussed, the error log buffer has only a limitedamount of space in which to record error information. Therefore, anerror log counter is provided which counts the number of error codeslogged in the memory. For lower rank errors, the error log counter isincremented by one. However, for higher ranked errors, the error logcounter is incremented by ten for each occurrence logged. In thismanner, higher rank errors effectively "fill-up" the error log morequickly than less serious errors. By way of example, assuming the errorlog can retain information on up to 255 error codes, incrementing theerror log counter by 10 every time a high rank error occurs means thatthe error log counter will indicate the error log buffer is full once 25high rank errors have been logged. In contrast, it would take 255 lowerrank errors for the error log counter to indicate the error log has beenfilled-up. As such, once the error log buffer begins filling up, and aslower rank errors are deleted from the list in favor of higher rankerrors, the error log buffer will eventually log only the most seriousof errors. This discrimination process increases the likelihood that theservice technician will diagnose and remedy the more serious errors,rather than being distracted by information regarding the less seriouserrors. In practice, it has generally been found that later occurrencesof higher rank errors provide more accurate fault diagnosis informationthan early occurrences of less serious errors.

The foregoing description of the presently preferred embodiment has beenprovided for the purposes of illustration. Therefore, one of ordinaryskill in the art can appreciate that modifications could be made withoutdeparting from the spirit or scope of the invention disclosed herein.

We claim:
 1. A control system for a vehicle having a convertible topcomprising a plurality of articulating support members and a tonneaucover, said control system comprising:a plurality of motive means formoving said support members and said tonneau cover to open and closesaid convertible top; a plurality of sensing means connected to certainof said support members and to said tonneau cover for sensing theposition of said members and said tonneau cover throughout their rangeof motion; and control means for interpreting said sensed positions andfor commanding said motive means to move said members and said tonneaucover in accordance with predetermined movements based upon saidinterpreted sensed positions, said control means further adapted forlogging errors whenever said members and said tonneau cover do not movein accordance with said predetermined movements.
 2. A control system setforth in claim 1 wherein said predetermined movements comprise a seriesof sequential movements, wherein each movement of said series movementsis adapted to prevent said members and said tonneau cover from collidingwith one another, and wherein when said interpreted sensed positionsindicate a collision is imminent, said control means commands saidmotive means to move said members and said tonneau cover to correctivepositions where no collision is possible.
 3. A control system as setforth in claim 2 wherein, after said control means has commanded saidmotive means to move said members and said control cover to one of saidcorrective positions and said interpreted sensed positions indicate saidmembers and said tonneau sever have not reached said correctiveposition, said control means logs misalignment error.
 4. A controlsystem as set forth in claim 2 wherein said control means is furtheradapted to measure the torque loading of said motive means, and whereinsaid control means commands said motive means to cease movement of saidconvertible top when said interpreted sensed positions indicate saidconvertible top is in a fully extended position when said control systemwas moving said convertible top from a retracted to an extended positionand said measured torque exceeds a predetermined torque for apredetermined length of time, and wherein said control means commandssaid motive means to cease movement of said convertible top when saidinterpreted sensed positions indicate said convertible top is in a fullyretracted position when said control system was moving said convertibletop from said extended position to said retracted position and saidmeasured torque exceeds said predetermined torque for said predeterminedlength of time.
 5. A control means as set forth in claim 4 wherein saidcontrol means logs an overload error whenever said measured torqueexceeds said predetermined torque for said predetermined length of timeand said interpreted sensed positions indicate said convertible top isnot in said fully extended position or said fully retracted position. 6.A method for commanding movement of a convertible top and for monitoringpositional information of said convertible top as it is extended andretracted, said method comprising:determining the desired direction ofmotion as being either extend or retract; determining the position ofsaid convertible top; commanding said convertible top to move towardsaid extended position when said desired direction of motion is extendand commanding said convertible top to move toward said retractedposition when said desired direction of motion is retract; commandingsaid convertible top to cease moving when said determined positionindicates said convertible top is in said extended position and saidconvertible top was being commanded to move toward said extendedposition, and commanding said convertible top to cease moving when saiddetermined position indicates said convertible top is in said retractedposition and said convertible top was being commanded to move towardsaid retracted position; commanding said convertible top to move towardneutral positions when said determined position indicates saidconvertible top is not moving toward said extended or said retractedposition in accordance with predetermined normal positions; and loggingerrors whenever said determined position indicates said convertible topcannot move toward said extended position when being commanded to movetoward said extended position and when said determined positionindicates said convertible top cannot move toward said retractedposition when being commanded to move toward said retracted position. 7.A method as set forth in claim 6 wherein said method furthercomprises:monitoring the torque exerted when moving said convertibletop; commanding said convertible top to cease moving when saiddetermined position indicates said convertible top is in said extendedposition and said monitored torque exceeds a predetermined threshold fora predetermined length of time and said convertible top was beingcommanded to move toward said extended position, and commanding saidconvertible top to cease moving when said determined position indicatessaid convertible top is in said retracted position and said monitoredtorque exceeds said predetermined threshold for said predeterminedlength of time and said convertible top was being commanded to movetoward said retracted position; and logging errors whenever saidmonitored torque exceeds said predetermined threshold for saidpredetermined length of time and said determined position indicates saidconvertible top is not in said extended or retracted position.
 8. Acontrol system as set forth in claim 1 wherein said control meansinhibits said convertible top from raising or lowering if said vehicleis moving.
 9. A control system as set forth in claim 8 wherein saidcontrol means monitors a transmission shift lever to determine if saidvehicle is moving.
 10. A control system as set forth in claim 8 whereinsaid control means monitors wheel speed to determine if said vehicle ismoving.
 11. A control system as set forth in claim 1 wherein saidcontrol means inhibits a trunk lid of said vehicle from opening whensaid convertible top is raising or lowering.
 12. A control system as setforth in claim 11 wherein said control means inhibits said trunk lidfrom opening by disabling a power trunk release.
 13. A control system asset forth in claim 1 wherein at least one window of said vehicle isautomatically lowered by said control means when said convertible top isset in motion.
 14. A control system as set forth in claim 1 wherein saidplurality of motive means includes a plurality of DC motors, whereinsaid plurality of DC motors can be manually back driven in the event ofan electrical system failure.
 15. A control system as set forth in claim1 wherein said control means employs a current wetting scheme duringpower-up of said control means, said current wetting scheme providing ashort burst of electrical current through said motive means to ensurethat connectors and relay contact points of said motive means do notbecome corroded.
 16. A control system as set forth in claim 1 whereinsaid control means transmits a status signal to an alarm system of saidvehicle indicating whether said convertible top is up or down.
 17. Amethod as set forth in claim 6 wherein said method furthercomprises:determining whether a vehicle containing said convertible topis moving; and inhibiting said convertible top from raising or loweringif said vehicle is moving.
 18. A method as set forth in claim 17 whereinsaid method further comprises inhibiting a trunk lid of said vehiclefrom opening when said convertible top is raising or lowering.
 19. Amethod as set forth in claim 18 wherein said method furthercomprises:providing a short burst of electrical current through a motivemeans to ensure that connectors and relay contact points of said motivemeans do not become corroded.
 20. A control system for lowering andraising a convertible top in a vehicle, said control system comprising:aplurality of motive means for raising and lowering said convertible top;a plurality of sensing means connected to said convertible top and tosaid vehicle for sensing the position of said convertible top throughoutits range of motion and the speed of said vehicle; control means forinterpreting said sensed positions of said convertible top and saidvehicle speed, wherein said control means commands said motive means tomove said convertible top in accordance with predetermined movementsbased upon said sensed positions if the speed of said vehicle is zero,said predetermined movements including a series of sequential movements,wherein each sequential movement of said series is adapted to preventmembers of said convertible top from colliding with one another, andwherein when said sensed positions indicate a collision is imminent,said control means commands said motive means to move members of saidconvertible top to corrective positions where no collision is possible.21. A control system as set forth in claim 20 wherein said convertibletop includes a plurality of articulating support members and a tonneaucover member.
 22. A control system as set forth in claim 20 wherein saidcontrol means is further adapted for logging errors whenever members ofsaid convertible top do not move in accordance with said predeterminedmovements.
 23. A control system as set forth in claim 20 wherein saidcontrol means is further adapted to measure the torque loading of saidmotive means, and wherein said control means commands said motive meansto cease movement of said convertible top when said sensed positionsindicate said convertible top is in a fully extended position when saidcontrol system was moving said convertible top from a retracted to anextended position and said measured torque exceeds a predeterminedtorque for a predetermined length of time, and wherein said controlmeans commands said motive means to cease movement of said convertibletop when said sensed positions indicate said convertible top is in afully retracted position when said control system was moving saidconvertible top from said extended position to said retracted positionand said measured torque exceeds said predetermined torque for saidpredetermined length of time.